Art of preserving cut flowers



Feb. 18, 1947,

E. ARLINGTON ART 'OF PRESERVING CUT FLOWERS Filed Jan. 8; 1945 3nnentor Alfred E.Ar1ingcon Gttomeg Patented Feb. 18,1947

" UNITED STATES PATENT OFFICE Alfred E. Arlington, fierkimer, N. Y.

Application J anuary 8, 1945; Serial N6.- 571,820

This invention relates to the preservation of cut flowers, during shipment and when used in cor sage bouquets; and florists arrangements such as sprays and set pieces used at funerals and for other purposes.

The usual prior art procedure was to insert the stems of out flowers into a mass of sphagnum mss saturated with water. As a rule flowers so used wilted in a few hours, and many desirable var eties wilted so quickly that their use was impracticable.

In his search for a better water retentive material applicant noticed a porous synthetic plastic material offered as a thermal insulator and produced by Goodyear Tire and Rubber Company, under the trade name Pliofoam. The manufacturers describe it as a urea-formaldehyde polymer of high molecular weight in the form of a rigid sponge-like structure having many minute cells. The cells comprise closed. bubbles in partial mutual contact but with interstices which form a continuous network. Thus there are two systems of air-filled voids, '(1) bubbles averaging 0.20 mm. in diameter and (2) a system of tube-like interstices, which latter o'fier means for the egress of liquids and vapors during drying.

As supplied, the material is chalk white and appears to be a solidified foam of extremely light weight. Blocks of it seem rigid but rather frail. The material is friable but has considerable mechanical strength. It weighs from 0.65 to 0.85 pound per cubic foot. It readily absorbs some water on contact, the diffusion being somewhat more active than that characteristic of ordinary blotting paper, but; penetration of water into a block of untreated Pliofoam is not deep. The material is stated to be non-toxic, insoluble in all solvents and resistant to dilute acids and bases, but subject to decomposition if subjected to maintained temperatures above 170? F. It may be cut smoothly with a knife or band saw. Under a compression load of 240 pounds per square foot the 03.65 pound per cubic foot Pliofoam compresses about 20% and about 40% under a load of 330 pounds. Its ultimate tensile strength is about 15 pounds per square inch.

Since Pliofoam, in the form above described, would absorb water to a considerable extent, is not excessive in cost, is reasonably stable in form, can be cut to shape and can be readily punctured by the insertion of stems, it appeared to be a promising material for applicants purpose.

Initial tests with it were disappointing, for used as delivered (except that itwas soaked with watei) it was not noticeably better than Sphagnum moss.

Subsequently, in manipulating a block of Pliofdin under water applicant discovered that by compressing the Pliofoam moderately beyond its elastic limit, its ability totake-up water was very 9 Claims. (Cl. 4741) 2 greatly increased. For example, a block originally 8" x 3" x 4 flattened under water so so verely that when released it only partly recovers to 8" x 3" x 3", will retain its structural integrity but become very heavily charged with water. A block of the size stated, when so treated, will absorb and hold not quite 20 ounces of water. Thus the charged block holds about 45% of its volume of water. The amount varies somewhat with the particular specimen of Pliofoam. This indicates, and it appears to be the fact, that compression ruptures the walls of most of the bub bles inthe Pliofoam adding their volume tothe continuous network. Moreover the capillary effeet is notably strong, so that there is very little seepage loss of water. Indeed the retainedwater in applicants finished product does not diminish in noticeable degree in periods several times the life of any cutflower.

The results of tests made by inserting the stems of cut flowers into blocks so saturated were remarkable. For example snapdragon not heretofore considered usable in set pieces lasted without wilting for 48 hours and similar results were had with delphinium.

For commercial use, the structure illustrated in the accompanying drawing was evolved. This comprises, as its essential element, a block I of Pliofoam compressed and charged with water as above'described. That is to say, the block is flattened under water until it will recover only about two-thirds of its original volume. It is then removed from the water and allowed to drain for about three minutes, after which it is squeezed very gently toremove water near the surface. The block is then sealed in an impervious envelope 2. The purpose of the envelope is to permit-saturated blocks to be kept in stock for longer periods than would otherwise be practicable, as well as to shroud the Verywet mass of Pliofoam when in use as the base of some flower arrangement.

A transparent bag made'of a synthetic plastic sold by the manufacturers of Pliofoam under the trade 'name of Pliofilm is of similar plastic material and therefore compatib1e,and has been found highly satisfactory.

The blocks may be cut to special shapes of any practicable size (either before or after impregnating with water) so as to conform to de.'- sired designs. Alternatively special shapes may be produced by assembling block units. The wa te'r-charged" Pliofoam blocks enclosed in envelopes retain their watercharge and do not support the growth of molds.

In using them, the envelope and the block are punctured at appropriate points, either by, or preparatory to the insertion of flower stems.

An important commercial advantage resides in the "fact that-the stems of most flowers will penetrate Pliofoam quite readily. In such cases the use of wired wooden picks is unnecessary. The resulting saving in time and labor is substantial. r

While the retention of water in adequate quantity under conditions whichmake it available to the flower stems is believed to be the principal factor in the success of the invention, careful tests show'that' water taken from the Pliofoam contains a minute quantity of formalde hyde, about five parts in one million.- This doubtless accounts for the resistance to mold growth and could account in some degree for the longereifective life of the flowers whose stems are inserted in it.

Whatever the cause, the facts have been demonstrated consistently by .tests :such as the fol lowing:

Flowers of several varieties were cut at the same time and placed-in cold water for five hours. This is standard florists procedure after cutting flowers. The flowerswere then divided into three groups as nearly identical as possible. The

stems of one group wereinserted in sphagnum moss wet with cold water and enclosed in a Pliofilm bag, those of the second were inserted in untreated Pliofoam soaked with cold water and enclosed in .a similar Pliofilm bag and'those of the third were inserted in Pliofoam treated according to theinvention and enclosed in a Pliofilmbag. All were placed in the same room at a temperature of. 72:F. The three water-holding bodies were all of. comparable size. and 2 wilted badly in twenty hours. No flowers in the third group wiltedin less than forty hours and some varieties-lasted fiftyhours. This particular test was selected as typical because conservative. Some other tests which have .been made offer even more favorable comparisons. I To afiord a, more direct comparison another test-eliminating the five hour period in cold water Groups 1 tegrity of the mass, whereby the cells form part 7 of a continuous capillary network. ,7

2. As a base for flower arrangements, ureaformaldehyde resin foam'of high'water-absorptive capacity in the form of a hardened mass of minute bubble-like cells in at least partial mutual contact, the walls of said cells having been ruptured after they have hardened, without destroyingthe integrity of the mass, whereby the cells form part of a, continuous capillary network.

3. A water-retaining base for receiving and supporting flower stems comprising a block of hardened resin foam in which minute bubblelike cells in partial mutual contact have been ruptured and charged with water. v,

4. The article defined in claim 3 in which the resin foam is of the urea-formaldehyde polymer type. V .7

5.. The article defined in claim 3 in which the water contains at least a trace of free formaldehyde. a

6. The method of preserving a cut flower which comprises overstressing anormally rigid mass of plastic foam sufliciently to rupture the walls of contained bubbles without otherwise materially impairing its structuralintegrity, saturating the mass with water, and using the mass so saturatedas a source of moisture for the stem of a I cut flower inserted therein,

1 was made. Carnations, sweet peas and snapdragon were cut at the same time and divided 1 into two groups as nearly identical as possible.

, Group 1 was immediately placed in a vase of adequate size about 12" deep and filled with 1 cold water. I ately inserted in a blockof Pliofoam saturated j with cold water according to the invention. Both groupswere placed inthe same room at .70" F.

Group 2 had their stems immediand were untouchedv thereafter throughout the,

test. r

Carnations-Group ,1 wilted at the end of .48 j hours and thosein group 2 wilted at the end of 1 44 hours.

Sweet peas-Both groups started to wilt at 1 the end of 82 hours.

Snapdragon.-'-Group 1 had wilted and the l flowershad shattered badlyat the end of 85 hours whereas group 2 was still presentable. The leaves in group 2'were healthy and rigid at the end of 85 hours whereas those of group 1 were dull and drooping. w u The foregoing results indicate that the in- 1 vention produces a portablewater retaining mass which will preserve cut flowers for periods comparable to those attainable by' theuse of free water. They'also raiseserious doubt as to the desirability of standing flowers .in cold Water as 1 a preliminary to their insertion in 'Pliofoam.

What is claimed is: s 1. As a base for'flower arrangements, plastic foam of high water-absorptive capacitycomprising. a hardened mass of. minute bubble-like cells inrat least partial mutual contact, the walls .of

inwater and to such anextent that the mass when released from compression will recover approximately two-thirds' of its original 7 volume;

releasing the mass from such compression,

whereby it absorbs water; removing the watercharged mass from the water in which it was submerged; and using'said mass as a source of moisture for the stem of a cut flower inserted therein.

8. The method of preserving a cut flower which comprises substantially completely charging with water the bubble-like cells of amass of dried plastic foam of such minute cellular structure that approximately the entire water chargeis retained by capillary action, and using the mass with its retained water charge as a source of moisture for the stemof the flower inserted therein." 7

.9. The method of preserving a cut flowenwhich comprises substantially completely charging with water the bubble-like cells of a mass of dried urea formaldehyde plastic foam of such minute cellular structure that approximately the entire water charge is retained by capillary action, and

using the mass with the retained water charge 2 as a source of moisture for the stem of the flower inserted therein. i

A Fann. E. ARLINGTON:

R FEnnNoEs CITED 7 I The following references areof record in the file of this, patent; g

UNITED [STATES PATENTS:

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